This invention relates generally to off-road motor vehicles, such as tractors, and more particularly, to an engine hood enclosure for the tractor engine in which the hood is rearwardly pivotable and closes against a radiator structure.
Tractors, particularly tractors used in an agricultural environment, are typically provided with a hood enclosure that has pivotable parts to provide access to the engine for service thereof. Generally, tractor hoods do not utilize engine hoods that pivotally move as an entire unit to provide access to the tractor engine; however, one piece hood configurations can be more economically produced.
In known engine hood configurations, access for daily maintenance components is attained merely by lifting or removing a side panel of the engine hood. Furthermore, raising the hood to fully expose the engine subjects the hood to wind forces, while daily maintenance, such as oil Level checking, etc., can be accomplished without fully raising the hood relative to the engine. Accordingly, it would be desirable to provide a rear hinged engine hood for a tractor in which the hood is pivotable in an upwardly and rearwardly direction and in which the hood is positionable in at least one intermediate position and further desirable to provide a mechanism to permit daily maintenance without requiring the raising of the hood.
Economical manufacture of a one piece engine hood enclosure is a desirable goal. One piece polymer hoods have the advantage of being molded in an aesthetically pleasing shape; however, certain manufacturing processes require the hood to have substantially uniform material thicknesses to accomplish a high gloss exterior finish and minimize tooling costs. Since a one piece, rear hinged hood closes against the radiator structure from a generally vertical direction, a corresponding sealing apparatus between the hood and the radiator would be desirable.
For proper engine cooling, the air gap between the radiator and the hood must be sealed to prevent hot air from re-circulating from the engine compartment back through the radiator. For known hood assemblies in which the hood structure does not move relative to the radiator for routine servicing of the engine, a strip of pressure sensitive, adhesive-attached closed cell foam is installed between the radiator and hood with little durability problems. When such closed cell foam is utilized in conditions under which the adjacent hood panels are moved relative to the seal for servicing, the seal often is subject to damage from environmental heat, chemical contamination and operator contact. This sealing problem is more troublesome when the radiator structure against which the hood is to be sealed is provided with irregularly shaped surfaces.
For a rear hinged hood structure that requires frequent movement for servicing the engine, the seals must be wear, chemical, temperature and peel resistant. Furthermore, the required closure against a radiator injects a temperature differential problem where the left inner cooler tube can reach temperatures of approximately 325.degree., while the right cooler tube may only reach a temperature of 170.degree.. The top of the radiator tank usually has an intermittent temperature reaching a high of about 250.degree.. Such a seal must be soft and easily compressed so that the forces to effect hood closure and latching are not excessive.
The shape of the hood provides an opportunity to improve visibility to the area of the ground inside of the front tires to improve the operation of the tractor when performing row crop work. A simple narrowing of the one piece hood along the sight line of the operator restricts the effective width of the engine compartment so that the hood can be raised vertically to service the engine. Such restrictions, however, are unacceptable, as large tractors require large engines and the hood must be adapted to the engine compartment.
Furthermore, the utilization of a one piece hood requires a vertical raising of the hood for servicing the engine. Daily servicing would be best achieved without requiring any vertical movement of the hood; however, the raising of the hood to access the engine and/or radiator structure requires sufficient vertical movement that the entire hood structure clears the engine compartment to permit open access thereto.